Technology
Ethernet APL offers continuous access to process data WITH NEW ETHERNET-APL COMMUNICATION technology, users in the process industries have gained a strong partner at their side in their quest for higher efficiency and increasing quality. This new form of data transmission will give digitalization a boost in process engineering production environments. Data from all areas of a process system will be connected in a secure and practical manner and made available from a central point. This helps users derive valuable information from vast amounts of data points. For years now, process control field instruments have been able not only to fulfill their measuring tasks but to supply additional information as well. In theory, this makes the installed base transparent and provides detailed instrument diagnostic information, which can be used for such things as preventive maintenance of the instruments. However, this added value can only be partially realized with the current technology. The 4–20mA analog technology, to cite one example, is suitable for process control tasks but not for further data access. The additional HART protocol, which today is used primarily for configuration of the instruments, is simply too slow for comprehensive data access. Fieldbus technology, known for many years, has improved this aspect, but is also still considerably slow. Furthermore, fieldbus technology has proven too complex for many users over the years and has consequently failed to fully establish itself.
Worlds growing together
A glance at other industries shows that Ethernet has not only become a standard in office environments but is also being utilized in industrial applications. The main advantage is the high speed and seamless integration into IT systems. “Only in the process industry have Ethernet specifications failed to meet the expectations of the operators up to this point,” says Benedikt Spielmann, Marketing Manager Industrial Communication at Endress+Hauser. “While Ethernet is a fast way to transmit data, all the components require a separate power source. That translates into extensive cabling effort and the associated higher costs. Furthermore, Ethernet has so far been restricted to 100-meter cable distances while 02.202 2
SOURCE: ENDRESS & HAUSER
Ethernet-APL brings real-time communication to the field in process systems. End-to-end Ethernet technology yields a wide range of benefits in terms of efficiency and simplicity. Users benefit from an integrated web server that simplifies remote access to field instruments.
Ready for use at the field level. With Ethernet-APL, digitalization will receive a boost in process engineering production environments. process systems often extend up to 1,000 meters. Another issue is that the RJ-45 plugs are not designed for harsh field environments. And so far the best argument against the use of Ethernet in the process industry has been the lack of suitability for ex-zones because of the absence of intrinsic safety.” Leading manufacturers and user organizations joined forces several years ago to eliminate these disadvantages. The APL Group established the goal of being able to utilize the basic advantages of Ethernet technology in process systems as well and to get Ethernet in shape for use at the field level in the process industry: power and data transmission via the same two-wire cable, suitability for ex-zones, high bandwidth and long cable distances. Work on the specification has now been completed. The technology was made public during the virtual Achema 2021 conference. “The launch of Ethernet-APL technology during Achema Pulse was an important milestone,” according to Benedikt Spielmann. “All the specifications and guidelines were completed on schedule. The presentation of the first Ethernet-APL instruments on the multi-vendor APL exhibit wall was a striking illustration that all the participating manufacturers are working on their APL portfolios. There were
i n d u str i a l e th e r n e t b o o k
also insights into which customer applications would benefit from the new technology.”
APL project work packages
One of the primary tasks of the working group was to guarantee intrinsic safety, which first required limiting the power transmission. This requirement initially contradicted the desire for higher bandwidth, long cable distances and robustness against electromagnetic interference. Questions related to the cable and plug or type of connection had to be answered as well. All of the challenges were successfully addressed. The solution is reflected in various working papers, standards and documents: 10BASE-T1L: The IEEE802.3cg-2019 specification defines the full duplex 10 MB data transmission via two-wire cable at distances of up to 1,000 meters. This is also the basis for the production of physical layer components (microchips for coding and decoding in Ethernet-APL devices). 2-WISE: This concept for two-wire intrinsically safe Ethernet (2-WISE) is based on the fieldbus intrinsically safe concept (FISCO). Migration to existing fieldbus installations is simplified through compatible ex-i parameters, and simple installation without extensive validation in ex-zones is ensured.
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